@CittyKat112 I was using MBF21, the format specified in the first post- so, it should be fine in DSDA- at least, according to what was said. I'm at work, so I'll have to wait until I get home to try your fix- my problem so far has been that I haven't been able to find the .exe for it. Like, it's got all the files, but nothing to run it- otherwise I'd have already tested it in that. Though, if PRboom runs MBF21, I'll just test it there.
[EDIT]
So i'm a dumbass. the version i downloaded didn't have the .EXE, i've confirmed that, but i found the version that does, so...Yeah.